It is expected that several identical Point Absorber Wave Energy Converters (PAWECs) will be arranged in arrays to form a Wave Energy Farm. One of the key challenges in designing such a WEC array is their spatial configuration, as the WECs in the farm interact hydrodynamically with each other. This study focuses on different potential PAWEC deployments to identify the best relative position in order to maximise energy output. This is done by resolving the hydrodynamic interactions between a modelled WEC point absorber, with use of open-source Boundary Element Methods (BEM) and time domain WEC simulator. The results from the numerical model are also compared with wave tank testing, to verify the accuracy of the analysis. The simulations show that the relative position can significantly increase a WEC’s individual power output. A spatial pattern of relative positions that result in higher potential power extraction was shown, with increases up to 20% compared to a single WEC on its own. However, the computational results showed realistic results for only a select number of configurations. As for the experiment, unexpected variations in test conditions occurred, inhibiting the possibility to isolate certain events. Therefore, when cross checking results from both simulations and experiments, the identified simulated trends only partially showed adherence with the experimental data. Henceforth, the knowledge gathered from the simulations can’t conclusively be validated by the experiments conducted in this study. This study shows that the spatial configuration of two WECs influences their individual power outputs.@en

The study quantifies socio-economic benefits by the integration of wave energy in Greece, through resource examination, availability and deployment considerations. Greece has a large number of inhabited islands that mostly utilise conventional fuels for power generation, inclusion of wave energy will contribute both in terms of energy independence but also in job creation. The Greek region is often overlooked, due to its lower resources, but through proper converter selection energy benefits can be significant. Furthermore, milder resources offer opportunities for capital expenditure reductions, hence reducing cost of device and energy.

Scenarios consider technological maturity, legislation, and resource potential to quantify future cumulative installations that can be developed. If a wave energy converter (WEC) is selected properly, accounting for climate variability and persistence, an off-the-shelve WEC can operate at capacity factors starting from 20%. Based on a resource and availability assessment, the learning rates from an incremental approach are more suitable and allow cost reductions. Job creation targets island regions where majority of exploitable resource is located and can provide up to 1400 direct jobs. Adaptation of wave energy by Greece has the potential to offer major technological, energy and employment benefits.@en

To properly assess the energy and waves at a region, it is vital to obtain suitable long term metocean conditions. Although, wave buoys are a significant source of information they are not able to provide a detailed and complete resource assessment, as they have inherent spatiotemporal and recording limitations. Therefore, numerical wave models are often used to estimate wave power and metocean conditions. A wave model can provide realistic representation of physical processes, but it should entail careful tuning of parameters, which are often based on empirical and semi-empirical configurations. The study presents calibration of a wave numerical model and examines its performance, for nearshore wave assessments. Parametrisations of wind growth and whitecapping coefficients have direct effects on evolution of locally generated waves, swells, and can reduce uncertainty in the results of a hindcast. The results are used to explain the physical meaning of differences, and provide a detail comparison of metocean parameters with nearshore and shallow water buoys as in-situ benchmarkers. Inter-model comparisons also indicate differences in spatial wave generation and propagation, as affected by wind growth and dissipation rates. The “optimal” solution will result in a model that will be used to provide a long-term high resolution metocean and wave power assessment for the Netherlands, that so far has been lacking in wave energy resource characterisation.@en

Growing energy demand has increased interest in marine renewable energy resources, i.e. wave energy which is harvested through Wave Energy Converter (WEC) Arrays.
However, the wave energy industry is currently at a significant juncture in its development, facing a number of challenges which require that research re-focuses on a holistic techno-economic perspective, where economics consider the full life-cycle costs of the technology. It also requires development of WECs suitable for niche markets, because in Europe there are inequalities regarding wave energy resources, wave energy companies, national programmes and investments. As a result, in Europe there are leading and non-leading countries in wave energy technology. The sector also needs to increase confidence of potential investors by reducing (non-)technological risks. This can be achieved through an interdisciplinary approach by involving engineers, economists, environmental scientists, legislation, governmental bodies and policy experts. Consequently, the wave energy sector needs to receive the necessary attention compared to other more advanced and commercial ocean energy technologies (e.g. offshore wind).
The formation of the first open pan-European Network on an interdisciplinary approach will contribute to largescale WEC Array deployment by dealing with the current bottlenecks. The WECANet European COST Action, introduced in September 2018 and presented in this paper, aims at a collaborative and inclusive approach, as it provides a strong networking platform that also creates the space for dialogue between all stakeholders in wave energy. An important characteristic of the Action is that participation is open to all parties interested and active in the development of wave energy. Previous activities organised by WECANet core group members have resulted in a number of joint European projects and scientific publications. WECANet’s main target is the equal research, training, networking, collaboration and funding opportunities for all researchers and professionals, regardless of age, gender and country in order to obtain understanding in the main challenges governing the development of the wave energy sector.@en

With the renewable targets of 2020 reaching ever closer, Europe is continuing its ambitious plans for 2030 of developing innovative projects that assist tackling climate change and increase renewable energy integration. The Netherlands are trying to develop their renewable energy portfolio, to create a viable long-term decarbonized sustainable society. So far majority of development has been focused on wind and solar, with offshore wind gaining significant traction over the past years. However, for the renewable energy transition to be fully realised, all indigenous resources must be evaluated and utilized. The Netherlands have a long history of dealing with water, and have an extensive industrial base in ocean engineering and water infrastructure. However, when it comes to the development of wave energy the sector is lacking significantly compared to other offshore renewables. This study discusses the past, present and future status of wave energy in the Netherlands. We discuss the various schemes and propose a hybrid support scheme for the development of wave energy. Furthermore, we also consider the unique spatial characteristics of the coastlines and suggest a multizonal scheme, that can act beneficially and support development of different wave converter concepts. Finally, based on the spatial and a techno-economic, we propose that by 2030 the policy focus should be to install up to 24 MW and by 2040 to 44 MW, with initial estimations on reductions per Unit Cost also discussed. With wave technologies in early stages of development in terms of technology and regional applications, there are numerous opportunities that can assist in “unlocking” the wave energy industry in the Netherlands.@en

The New Entrance Reserve (NER300) is one of the leading mechanisms used for the application and promotion of clean energy projects. In this context, this study aims to investigate the evolution of wave energy projects within the first and second call of NER300. Furthermore, the study tries to identify the reasons of successful applications through an estimation analysis of energy production, avoided emission and energy security. Milder resources contain ‘hidden’ opportunities for wave energy, with lower expenditure and capacity factors equivalent and even over 20%. Lower extreme events indicate that associated installation costs can be considered reduced, thus the potential cost of energy may act as a positive driver for future development. The results of the study argue that there are regions with ‘hidden’ opportunities that can accelerate proof-of-concept and enhance viability for wave energy.@en

Renewable energy offers significant opportunities for electricity diversification. South Africa belongs to the group of developing nations and encompasses a lot of potential for renewable energy developments. Currently, the majority of its electricity production originates from fossil fuels; however, incorporation of clean coal technologies will aid in reaching the assigned targets. This study offers a long-term wave power quantification analysis with a numerical wave model. The investigation includes long-term resource assessment in the region, variability, seasonal and monthly wave energy content. Locations with high-energy content but low variability pose an opportunity that can contribute in the alleviation of energy poverty. Application of wave converters depends on the combination of complex terms. The study presents resource levels and the joint distributions, which indicate suitability for converter selection. Depending on the region of interest, these characteristics change. Thus, this resource assessment adds knowledge on wave power and optimal consideration for wave energy applicability.

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The study uses a 35-year data set, which can be used to provide a long-term assessment for assessing wave power resources, availability for wave energy converters (WECs), and multithreshold accessibility suitable for numerous vessels and important for offshore maintenance operations. The data set demonstrates that winter months have harsher environmental conditions for the Western regions, such as the Spanish coastlines, and the Eastern regions, such as the Aegean Sea, record slightly higher waves during summer months. The data set also identifies the seasons with lower resources, which will have higher accessibility and will benefit offshore construction and maintenance operations for offshore energy activities. It has been shown that the availability for wave energy depends on the operational range of a particular type of WEC; hence, threshold selection affects the availability distribution more than accessibility. Availability varies per region, with Southern Aegean, Southern Italian, and North African coasts having higher monthly values. Accessibility in nearshore areas is constantly over 90%, with deeper waters presenting reduced levels. Statistical analysis performed for this work shows predictable availability due to lower maxima, potentially enhancing WECs operation; this, however, will depend on device properties. Furthermore, the resource analysis indicates that the dominantmetocean conditions yield low wave height range.

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The study focuses around the energetic waters of Scotland that has expressed high interest in the development of wave energy farms. There are only a few long-term suitable studies characterising coastal locations. A detail coastal resource assessment is provided, focusing on wave energy and site characterisation. Mean nearshore energy content in the Western coasts is ≥50 kW/m and on the East ≈10 kW/m. Monthly and seasonal analyses outline available resource and annual variations. Availability of production is also examined, West coastlines present higher levels, however, depending on resource and wave converters operational range significant differences are shown. Availability levels on the East coastline are low ≈40% due to lower wave heights, while Western locations record consistently over 80% at both scenarios examined. Results discuss the potential applicability of favourable wave converters, and characteristics which achieve maximum utilisation based on the local environment.

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At autonomous electricity grids Renewable Energy (RE) contributes significantly to energy production. Offshore resources benefit from higher energy density, smaller visual impacts, and higher availability levels. Offshore locations at the West of Crete obtain wind availability ≈80%, combining this with the installation potential for large scale modern wind turbines (rated power) then expected annual benefits are immense. Temporal variability of production is a limiting factor for wider adaptation of large offshore farms. To this end multi-generation with wave energy can alleviate issues of non-generation for wind. Spatio-temporal correlation of wind and wave energy production exhibit that wind and wave hybrid stations can contribute significant amounts of clean energy, while at the same time reducing spatial constrains and public acceptance issues. Offshore technologies can be combined as co-located or not, altering contribution profiles of wave energy to non-operating wind turbine production. In this study a co-located option contributes up to 626 h per annum, while a non co-located solution is found to complement over 4000 h of a non-operative wind turbine. Findings indicate the opportunities associated not only in terms of capital expenditure reduction, but also in the ever important issue of renewable variability and grid stability.@en

Significant advancements have been made in the past few decades (since the 1980s) on detailed evaluation and quantification of wave resources globally. Larger availability and advances of computational resources have contributed to the utilisation of numerical wave models as powerful tools in climatic and energy studies. This review presents current state-of-the-art numerical tools and their status in the process of wave power assessments. We focus on the evolution of studies undertaken at the European coastline regions and the Black Sea. Although, a number of studies have been successfully developed and implemented in the past contributing to our understanding of the resource, this paper discusses the benefits, limitations and potential for improvement of numerical tools. From the literature, it is evident that different applications and scale may require different models, however, it is also the experience and knowledge of the user, applied in the tuning of a number of parameters that govern the process of wave generation, propagation, and the quality of input parameters that are the cornerstones of a successful model. This review depicted that the use of numerical wave models, depending on specific region and application, offers significant benefits on quantification of coastal zone wave resources which benefit multiple offshore applications and the energy industry.

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The study enhances the coastal resource knowledge and discusses opportunities for wave energy in the Aegean Sea. A fine-resolution numerical wave model is utilised to provide results for the Greek coastal regions. The model ran for 35 years (1980–2014) estimating wave characteristics, and quantifying the wave energy potential in coastal areas. The results deliver the energy potential, variability, and site characterisation for the Aegean Sea. The dataset is coupled with wave energy converters power matrices to provide for the first time a long-term analysis of expected power production. Performance of devices is highly dependent on matching the power matrix to the local resource, suitable devices can obtain capacity factor up to 20% and favour operation for low wave heights and high frequencies. Based on energy analysis data, an economic performance and payback period of a hypothetical wave farm is examined. With little information on wave energy in the region, this preliminary cost-to-benefit analysis shows the viability of wave converters. Even with high capital expenditure associated with novel technologies, certain scenarios achieve amortization periods at 7.5 years for a properly selected converter. Results are comparable with previous renewable schemes aimed at increasing the cumulative installation of other early stage technologies.

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Wave energy is expected to play an important role in the forthcoming years for the de-carbonisation of Scottish and British electricity production. This study underlines the importance of resource assessment and attempts to improve the quantifiable wave power resource, with use of a validated numerical model. While levels of wave flux are high for an area that may not always constitute the best option for wave energy applications. In this study, a long-term hindcast for the Scottish coastlines run from 2004 to 2014 (11 years) improving the existing wave maps and resource estimations. Spatial and physical considerations of a third generation spectral model allow examination at locations of immediate interest for the ocean energy community. Utilising numerical wave models of finer resolution allows for the detailed coupling of potential wave energy converters (WECs) and site characterization. Such detail energy results allow for improved financial analysis that take into account the severity of local resource and its energy potential.

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Many islands have high electricity prices due to the reliance on imported diesel. However, hybrid energy systems (HES) which combine renewable generation with backup generators and energy storage are becoming cost competitive. Diesel usually provides about 10% of the demand because most renewables are non-dispatchable and thus the complete decarbonisation requires massively oversized renewable generation and storage. By including renewables with different resource profiles and demand side management (DSM), the diesel consumption could be decreased without increasing storage and renewable generation capacities. Here a framework for the design and optimisation of HES using wind, wave and solar generation and DSM is introduced. For the Mediterranean it is shown that wave energy is not competitive but that DSM reduces the emissions and costs by 21 and 8%. In the North Sea, DSM has lower benefits because waves act as an energy store for the wind. Thus, the combination of wave energy converters (WECs) and wind turbines significantly reduces the need for backup generation and energy storage which leads to large reductions in costs (up to 40%) and emissions (up to 60%). DSM and WECs can both simultaneously reduce the cost and emissions of HES but need to be designed for the particular circumstances.

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Greece is a country that has numerous islands depending on conventional fossil fuels with electricity, fuel and transportation costs often subsidized by the State resulting in significant economic burdens. Small islands can benefit from adaptation of renewable energies to enhance their energy independence and promote sustainable development. In Greece majority of renewable sources utilized are wind and solar, however an un-tapped and under-investigated resource is wave energy. The wave resource encompasses higher energy density than wind and can contribute in the development of renewable energies, enhancing security of supply for smaller communities. Offshore locations offer significant advantages for renewable energy deployments with little interference on human activities and local ecosystems, hence reducing potential conflicts of interest and increasing social acceptance. Wind and wave resources differ in availability, in terms of energy production wind turbines can be estimated quite straightforward, on the other hand wave energy converters (WECs) require complex consideration and resource implication on energy production. Pending on regional focus different WECs are suitable, leading to different production profiles with WEC selection highly dependent on local long-term metocean condition. This study quantifies the temporal overlap by offshore wind and wave converters, in several locations around Greece using wind and wave data. Temporal overlap on energy production over long periods leads to robust results concerning the potential benefits by offshore devices.@en

The study focuses on a high resolution coastal assessment for the Libyan Sea at the South-West Mediterranean. To date majority of information for the area, are based on large scale oceanic models with coarse resolutions not adequate for nearshore assessments. This dataset and analysis provides an in-depth wave energy resource assessment and detail dissemination of sites according to their metocean characteristics. Identification for wave energy is based on the database constructed, allowing the quantification of energy levels and resource implications at sites. Mean values of wave heights around the coastlines are ≈1m, though high storm events exceed 5 m at several areas. Highest wave energy resources are located at open coastal areas, with energetic months reaching up to 10 kW/m. Low energy seasons are found throughout summer months, where energy content is reduced threefold. The resource can be classified as low, however the coefficient of variation suggests a predictable resource with extreme events not expected to surpass 10 m. Although, resource is not as energetic as open oceanic regions the low variations may assist wave energy as a supporting renewable energy option. Assessing the wave climate around the coasts for a long period of time can also provide confident and robust suggestions on the selection for wave energy converters. In addition, lower extreme events are expected to reduce potential installations costs by lowering structural expenditure and strengthening works to facilitate operation at milder environments.

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Wind is the dominant process for wave generation. Detailed evaluation of metocean conditions strengthens our understanding of issues concerning potential offshore applications. However, the scarcity of buoys and high cost of monitoring systems pose a barrier to properly defining offshore conditions. Through use of numerical wave models, metocean conditions can be hindcasted and forecasted providing reliable characterisations. This study reports the sensitivity of wind inputs on a numerical wave model for the Scottish region. Two re-analysis wind datasets with different spatio-temporal characteristics are used, the ERA-Interim Re-Analysis and the CFSR-NCEP Re-Analysis dataset. Different wind products alter results, affecting the accuracy obtained. The scope of this study is to assess different available wind databases and provide information concerning the most appropriate wind dataset for the specific region, based on temporal, spatial and geographic terms for wave modelling and offshore applications. Both wind input datasets delivered results from the numerical wave model with good correlation. Wave results by the 1-h dataset have higher peaks and lower biases, in expense of a high scatter index. On the other hand, the 6-h dataset has lower scatter but higher biases. The study shows how wind dataset affects the numerical wave modelling performance, and that depending on location and study needs, different wind inputs should be considered.@en

Waves are characterised by high energy density content, able to provide significant renewable energy contribution. Identification of wave energy potential locations around Europe can provide significant benefits for application of wave energy converters (WECs). While the highest resources are placed in the open Atlantic coastlines of Europe that does not exclude the fact thatwave energy can provide significant contributions to the rest of Europe. To support such claims, a detail resource assessment has to be in place to characterize the resource. State of-the-art resource assessments provide a tool that can identify trends in the resource and proper evaluation of production, based on such long-term data allows robust financial and engineering decisions. In addition, the results can also be used for climate investigations, extreme value analysis, site characterization, and information concerning a variety of offshore activities. This study investigates the metocean conditions of the Mediterranean Sea and assesses the levels of energy around the Basin. Hidden opportunities lay in both energetic and milder wave environments with each having each own benefits and drawbacks, in terms of capital costs required and energy production. The results from the hindcast underwent a detailed annual, seasonal, and decadal analysis. Furthermore, potential benefits of wave energy converters (WECs), are assessed in terms of energy production, adaptability, and final considerations for site selection are discussed.@en

Wave energy sites around Scotland, are considered one of the most energetic waters, as they are exposed to the Atlantic Ocean. The amount of energy reaching the shoreline provides an opportunity for wave energy deployments. Currently, considerations on wave devices expect them to be installed at nearshore locations. That means that the potential wave resource has to be investigated, since deep to shallow water interactions alter the shape of propagated waves. Resource assessment for these regions is essential in order to estimate the available and extractable energy resource. Although several numerical models exist for wave modelling, not all are suitable for nearshore applications. For the present work, the nearshore wave model SWAN has been used to simulate waves for the Hebridean region. The set-up, calibration and validation of the model are discussed. The resulting wave conditions are compared with buoy measurements. Results indicate that the modelling technique performed well.@en